Moulded container having integral reinforcing



MOULDED CONTAINER HAVING INTEGRAL REINFORGING Filed NOV- 6, 1968 p 1970P. J. a. GIRAUDET ETAL 2 Sheets-Sheet 1 FIG.I v

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MOULDED CONTAINER HAVING INTEGRAL REINFORCING Filed Nov. 6. .1968 2Sheets-Sheet 2 Il/an raxl,

451W I'M Patented Sept. 8, 1970 Int. Cl. Biasd 43/12 US. Cl. 220-41 6Claims ABSTRACT OF THE DISCLOSURE Moulded container having improvedtearing and buckling strength properties, wherein reinforcements areprovided on at least a portion of the inner surface of the containerside walls, so as to construct strengthening beams adjacent the upperand lower edges of said side walls.

The present invention relates to moulded containers which can be stackedonto each other and may be used particularly for the shipping andstocking of perishable goods. The invention relates also to a processfor improving the mechanical strength of such moulded containers.

Some containers have been known to be made by moulding foamed orexpanded plastic material such as expanded polystyrene, having goodisothermal properties, low weight, good tightness and good resistance toinsect and parasite attack.

Known containers of this type have an open top face and can beoptionally closed with a cover placed on the container body. Generally,the lower edges of these containers are perpendicular, whereas theirinternal surface has an arcuate profile over the entire bottom peripheryto allow for easier stripping from the mould and easier cleaning of thecontainer bottom. The remainder of the side Walls of such containershave a constant thickness up to the upper edge which is cut at rightangles to provide a good support for another container directly stackedonto the first one.

Such a construction of the container walls has a disadvantage when thecontainer is made of expanded polystyrene or the like. Thus it has beenobserved that when a rupture is initiated at the bottom end walls of thecontainer, due for example to shock or impact, the rupture grows up veryquickly over the entire height of the wall even if this wall isrelatively thick, causing the container to splinter.

Further, when the container is submitted to high loads, for example inthe stacking of a plurality of filled containers, a buckling or lateraldistortion of the walls often occurs, resulting immediately in completetear of one or several walls over their entire height. This buckling orlateral distortion and the resulting deterioration of containers andcontents thereof occur quite often on boats because, due to rolling andpitching, the center of gravity of the stack or pile of containers movestowards the outside of the pile and side walls of the containers slantmore or less with respect to vertical. It has been suggested to overcomepartially this disadvantage by thickening the walls of the containers inorder to increase stiffness, and buckling strength thereof. But thisentails a considerable increase of the amount of the material needed formanufacturing the container, and of the unitary cost of the same.

According to the instant invention, there is provided a process allowingfor a substantial increase of the buckling strength and the resistanceto the splitting of the side walls of this type containers, whiledecreasing the amount of needed raw material. According to theinvention, an inwardly projecting flange is provided on at least aportion of the upper periphery of the container, by means of a mouldhaving conveniently constructed movable parts. Due to this arrangement,there is also provided a fillet or profiled reinforcement between thelower face of said flange and the internal face of the correspondingside wall of the container. Another symmetrical profiled reinforcementis provided on the internal face of the container along its lowerperiphery. Thus, at least some of the container side walls are formed,at their bottom and at their top, with L-shaped channels. Besides,because the internal angle of these L-shaped channels is provided with areinforcement, the thickness of the corresponding walls is relativelylarger along the upper and lower edges, thus constituting reinforcingbeams.

Thus the wall together with the upper flange and the adjacent part ofthe bottom, forms a U-shaped profile which presents all the obviousadvantages of such a profile as far as the buckling strength and tearingstrength are concerned, as compared to the corresponding L-shaped partsof known containers. The reinforcing beams provided along the lower andupper edges of the wall enhance this desirable effect by firmlymaintaining the sheet constituting the wall. When the wall issufiiciently high, the overall thickness of the container walls can besubstantially decreased according to the process of the invention, whichconstitutes a compensation for the supplementary raw material necessaryfor making the upper flanged and arched portions and yet allows forobtaining stronger walls having an improved buckling strength not onlyin a lateral direction with respect to the beams, that is to sayhorizontally but also in a vertical direction, which is normally themost important feature. The central portion of the walls constitutes aveil-like web fixed up between the upper and lower beams.

A flat cover can be provided to close the container of the invention.This cover is preferably sliding and provided on two of its oppositeedges with projecting ribs capable of cooperating with complementarylongitudinal grooves provided in the corresponding inwardly projectingupper flanges. Alternatively, there can be provided a raisable coverhaving flared edges supported on the flared upper flanges of thecontainer, by a dovetailed stud fixing device.

Other objects and advantages of the present invention will be apparentto those skilled in the art when reading the specification and claimsappended thereto.

In the drawings:

FIG. 1 shows a cross-sectional view of the conventional container;

FIG. 2 is a cross-sectional view of a container according to theinvention;

FIG. 3 shows a perspective view of an embodiment of the container of theinvention having a sliding cover;

FIG. 4 is a cross-sectional view of the container of FIG. 3, showing theupper flange and the reinforcements;

FIG. 5 is a cross-sectional view of a wall of a container according toanother embodiment of the invention;

FIG. 6 is a cross-sectional view showing the jointed portion of a mouldclosed on the internal face of the side wall of a container according tothe invention;

FIG. 7 is a cross-sectional view showing the same parts as those of FIG.6, the jointed portion of the mold being separated from thecorresponding part of the container;

FIG. 8 is a perspective view of still another embodiment of a containeraccording to the invention, having an upper flange on its four sides andclosed by a cover;

FIG. 9 is a perspective view of a further embodiment of a containerprovided with the upper groove on both its longer sides, and dovetailednotches for receiving the cover;

FIG. 10 is a perspective view of the cover of the container shown onFIG. 9;

FIG. 11 is a perspective view of another embodiment of the containerhaving said upper flange on three sides thereof and adapted to receive asliding cover; and

FIG. 12 is a cross-sectional view of the beams formed at the convergingangles of four containers of the invention, placed side by side andstacked by groups of two.

The container, preferably moulded of expanded polystyrene, has itsoutside shaped as a rectangular parallelepiped and comprises four sidewalls 1 and a bottom 2. The internal periphery of the bottom is roundedso as to form a reinforcement 5 between the bottom and the side walls.The top face of said container is provided with a removable cover 6.

According to an embodiment of the invention shown on FIGS. 2, 3 and 4,both the longer side walls are provided respectively, along their upperedge, with a flange 7 projecting toward the inside of the container. Thelower part of said flange 7 is extended toward the internal face of thecorresponding side wall by a reinforcement 8 symmetrical to thereinforcement 5 at the bottom of this side wall. The side walls 8 and 5are archor ogive-shaped. After withdrawing from the mould, the expandedpolystyrene object possesses a smooth surface crust having highermechanical characteristics than those of the inside of the mass. Thiscrust constitutes a reinforcing frame for the arch-shaped side wall 8and prevents the flange 7 from collapsing or breaking after an impact ofan abnormal downward pressure. Each flange 7 is formed on its edge witha longitudinal groove 9 extending over the whole length of the saidflange. Cover 6 is provided on its side edges with a rib 10 having aprofile complementary to the one of groove 9 which acts as a slide forthe cover.

Such an assembly overcomes the disadvantages of the conventionalcontainers of the considered type, such as the container shown in FIG.1; these disadvantages comprise: relatively higher fragility of the sidewalls, loss of useful volume at the bottom of the flange of the coverparticularly when such containers are arranged in rows, and relativelylarger amounts of raw material used to make the cover.

The flanges 7 and the grooves 9 are made simultane ously with theremaining portions of the container, using of a mould having severaljointed parts 11 and 12, according to a known technique (cf. FIGS. 6 and7). The minimum free space between the jointed parts of the mould isdetermined by the width divided by the flange 7 (see FIG. 7). Thethickness of the walls of the container at the level of the upperreinforcements 8 is preferably equal to their thickness at the level ofthe lower reinforcements 5 so as not to have an increased setting andcooling time prior to withdrawing from the mould. The covers, contraryto the known fitting covers used with known type containers, can bemoulded in an upright position so as to obtain more covers during onemoulding operation. Furthermore, because the cover is flat and has asmaller area than the upper face of the container, the amount of rawmaterial saved with the instant cover is important.

Openings 13 for the venting of contents of the container, or for thedraining of waste liquids (see FIGS. 6, 7 and 11) can be provided. Inthat case, conveniently arranged stubs 14 are mounted on thecorresponding jointed parts 11 of the mould. The stripping of the mouldfrom these openings 13 will be effected in the same way and preferablyat the same time and by the same element as the stripping of flanges 7and grooves 9.

According to another embodiment of this invention (shown on FIG. 11),the container has a flange 7 on three of its sides. The cover isintroduced into grooves 9 from the side which has no flange, it slidesin the groove of the two lateral flanges then contacts the oppositeflange at the end of its travel.

According to still another embodiment, shown on FIG. 5 and 8, the flange7 extends over the whole upper periphery of the container. The edge 15of said flange 7 is outwardly flared, the edges 16 of the four sides ofthe cover having a complementary flared profile. According to a furtherembodiment shown on FIGS. 9 and 10, the flared edge 15 of the flangecomprises dovetailing notches 17. Dovetailed stubs 18, shapedcomplementarily to notches 17, are provided on the periphery of thecover wherefrom they project in the area corresponding to the flaring.Marginal recessed notches 19 and/or median recessed notches 20 areprovided in the upper part of the cover to allow gripping thereof so asto separate it from the container. The cover is thus put in place andtaken out vertically. When the cover is put in place and the dovetailedstubs of the cover are inserted in their recesses on the container, thestability of the container is still further increased and the bucklingstrength of the side walls is maximum The containers according to theinvention can be stacked and stored side by side to form compact blocksin warehouses, store-rooms in ships, railway or road trucks. In thiscase, the buckling strength and tearing strength constitute an importanteconomy factor, for it determines the limit, in terms of stackedcontainers or in terms of height of the stack, beyond which it is nolonger possible to pile up containers without a risk of tearing orrupture. The stacking and placing side by side of identical containersaccording to the invention form at each of the points of juxtapositionof the container corners stack edges, composite beams 21 having largesections, said beams being constituted by the combination of the cornershaving reinforcements 5, of both up per containers 22, and of thecorners having flanges 7 and reinforcements 8, of both lower containers23 (see FIG. 12). The stability of each container of the block and thestiffness of the side walls thereof are substantially increased incomparison to conventional containers arranged in similar blocks, theadjacent walls 24 of both lower containers 23 being then comparable tomedian legs of two U-shaped back-to-back channels. These stability andstiffness are further increased when containers of the invention arefitted with their respective covers prior to stacking, since, then, theside walls of containers 23 which are opposed to walls 24 respectively,act as abutments.

Of course, the invention is not limited to the examples described andshown in the drawings and it can be modified in accordance with theshown embodiments Without leaving the scope of the invention.Particularly, reinforcements 5 and 8 can have a flat or semi-circularprofile, or one or both reinforcements can be omitted without any lossof the advantages of the invention. The fixing means of the cover canalso be modified according to the desired use of the container.

What is claimed is:

1. A stackable container made of a molded plastic material such asexpanded polystyrene, comprising a bottom wall and four side wallsextending upwardly from the peripheral edges of said bottom wall, thelatter being provided with a bottom edge reinforcement extending alongat least a portion of said peripheral edges of the bottom, and includingthickened angle portions defined by concave inner surfaces, saidthickened angle portions joining the inner faces of at least some of theside walls with the upper surface of said bottom wall, said side wallshaving a peripheral flange arranged at at least a portion of their upperedges and extending inwardly therefrom and having a concaveconfiguration, a fillet-like flange reinforcement extending in thecorner formed between each side wall and the corresponding portion .ofsaid flange.

2. The container of claim 1, wherein said peripheral flange comprisestwo opposite flange portions extending respectively along the upperedges of two opposite side walls and having each an inwardly directedsurface which is provided with a longitudinal flange groove, the twoflange grooves being adapted to receive slideahly opposite longitudinalend portions of a cover for closing the top end of said container.

3. The container of claim 2, wherein said longitudinal cover endportions are constituted by ribs which are slideably engageable in saidgrooves.

4. The container of claim 1, wherein the inwardly directed surface ofsaid flange is flared upwardly and outwardly, and wherein a cover havingits peripheral edges complementarily flared downwardly and inwardly ofthe container is adapted to be removably fitted onto the top end of saidcontainer.

5. The container of claim 4, wherein the flared flange faces areprovided with at least one detailed notch adapted to receive at leastone complementarily shaped stud provided at the periphery of said cover,whereby the latter is locked in place for closing the container top end.

6. The container of claim 4, wherein said cover has its top faceprovided with recesses adapted to receive the fingers of the user foreasy removal of said cover from said container.

References Cited UNITED STATES PATENTS 3,182,856 5/1965 Goltz 220-413,362,564 1/1968 Mueller 22041 3,403,714 10/1968 Hulm 150--5 GEORGE T.HALL, Primary Examiner US. Cl. X.R.

